Autotoxicity in cucumber (<Emphasis Type="Italic">Cucumis sativus</Emphasis> L.) seedlings is alleviated by silicon through an increase in the activity of antioxidant enzymes and by mitigating lipid peroxidation

Autotoxicity in plants limits their growth and that of nearby plants of the same species, which has obvious implications in crop yield and quality. Silicon (Si) has been shown to increase plant tolerance to autotoxic stress. However, the physiological mechanisms underlying the effects of Si in alleviating autotoxicity during germination in cucumber (Cucumis sativus L.) are unknown. Cinnamic acid derivatives, such as 3-phenylpropionic acid (PA), are a class of autotoxins present in cucumber root exudates. Our objective was to investigate Si-induced autotoxic stress tolerance in cucumber seedlings by focusing on the effects of Si on the induction of antioxidant defense pathways. We found that PA treatment significantly reduced seed germination, radicle length, lateral root number, fresh weight, AsA and GSH contents, and the activities of SOD, CAT, and APX in cucumber seedlings, while it increased membrane permeability and levels of MDA, proline, O₂^-, and H₂O₂. Application of Si enhanced growth of PA-treated plants and significantly increased germination rate, radicle length, lateral root number, fresh weight, AsA and GSH levels, and SOD, CAT, POD, and APX activities. These results suggest that exogenous Si alleviates autotoxicity caused by PA during seed germination by increasing antioxidant enzyme activities and mitigating lipid peroxidation.     

Enhanced production of harringtonine and homoharringtonine in Cephalotaxus fortunei callus culture by periodic temperature oscillation

Total production of harringtonine, homoharringtonine and isoharringtonine in solid cultures of Cephalotaxus fortunei was 1.22 mg/l by periodic oscillation in temperature between 10 and 25°C every 12 h for 45 days. Production was enhanced 1.8 and 1.3-fold compared to the controls at constant temperatures of 10 or 25°C. For suspension cultures subjected to such an oscillation every 24 h for 30 days, total alkaloid production of 0.18 mg/l was achieved, a 2.0 and 1.1-fold improvement compared to the suspension culture controls, correspondingly.     

Assessment of Sensitivities to Anilinopyrimidine- and Strobilurin-fungicides in Populations of the Apple Scab Fungus Venturia inaequalis

The sensitivity of Venturia inaequalis populations to the anilinopyrimidine fungicides pyrimethanil and cyprodinil was analysed by microscopic in vivo analysis of conidiophore formation. The sensitivity to the strobilurin kresoxim-methyl was analysed using an in vitro germination assay and by determination of the diseased leaf area and conidia produced in vivo. Baseline sensitivities were determined with V. inaequalis populations from control orchards that had never been treated with fungicides. Comparison of the baseline sensitivities with sensitivities of populations obtained from orchards that had received 43 anilinopyrimidine treatments over 4 years, or from an orchard with 54 kresoxim-methyl treatments over 6 years indicated that no resistance to these fungicides has developed at the sites sampled.     

Fluorescein Diacetate Uptake to Determine the Viability of Human Fetal Cerebral Cortical Cells

We investigated the accuracy of fluorescein diacetate uptake as an indicator of the viability of human fetal cerebral cortical cells. Cortical cells from 16-26-week-old normal fetuses were studied. The cortices were dissociated mechanically with normal saline to make a suspension. Fluorescein diacetate uptake and trypan blue exclusion were compared as methods for examining cell viability. Our results show that fluorescein diacetate uptake is a simple and sensitive method for examining human fetal cortical cell viability.     

Digital image analysis of chromatin fibre phenotype after "in situ" digestion with restriction endonucleases

Restriction Endonucleases (REs) may recognize, cleave and remove DNA from fixed chromatin producing specific chromosome banding patterns. However, the modifications produced in the chromatin fibre are not easy to evaluate and compare. The aim of the present investigation was to visualize differences resulting in the texture of the chromatin fibre from metaphase chromosomes after each digestion using digital image analysis (DIA) facilities. To this purpose, metaphase chromosomes derived from a L-929 mouse cell line were digested with different REs (AluI, HpaII and HaeIII). Since light microscopy does not permit the observation of the chromatin fibre, DIA was performed on digitalized images of metaphase chromosomes under electron microscopy. The application of a LUT (Look Up Table) within the DIA software assigns a colour to each grey level of a digital image. The results obtained using a particular LUT, which permits the discrimination of specific chromatin fibre phenotypes resulting from each digestion, are reported and compared with those obtained under the light microscope.     

猴脾脏内NPY、CGRP、SP 和 VIP免疫反应神经纤维的分布

本文应用 ABC 免疫组织化学染色法结合葡萄糖氧化酶-DAB-硫酸镍铵(GDN)显色技术,观察了神经肽 Y(NPY)降钙素基因相关肽(CGRP)、P 物质(SP)和血管活性肠肽(VIP)免疫反应(Immunoreactire,IR)阳性神经纤维在猴脾脏的分布。结果发现,NPY-IR 神经纤维沿脾的动脉、静脉及其分支走行,在被膜、小梁、白髓、红髓和边缘区亦有分布。CGRP-IR 和SP-IR 神经纤维在脾脏的分布相同,主要沿脾动脉走行,中央动脉周围尤为丰富,白髓和红髓的淋巴组织中有少许分布。VIP-IR 神经纤维主要分布在中央动脉周围,白髓和边缘区有零星分布。猴脾脏肽能神经纤维末梢与免疫细胞接触密切,揭示它们对免疫细胞的发育和活性具有调节作用。本研究为神经免疫调节机制提供了形态学依据。     

Regional vascular influences on tail-cuff measurements of drug-induced changes in systolic pressure.

When drug effects are quantified using the tail-cuff method, changes in systemic arterial pressure are extrapolated from those occurring in the caudal artery. The validity of this extrapolation was tested in anesthetized rats by recording drug-induced changes in phasic arterial pressure simultaneously from catheters inserted into the lower abdominal aorta, carotid, and caudal arteries. Pressor responses to norepinephrine or angiotensin were of equal magnitude at all three sites, but phentolamine reduced systolic pressure in the aorta or caudal artery more than that in the carotid artery. Unlike previous discrepancies between carotid and tail-cuff systolic pressures, aortic hypotension caused by injections of phentolamine or pentolinium in awake normotensive or spontaneously hypertensive rats was accurately predicted by the tail-cuff method. Because drug-induced changes in diastolic pressure always varied much less than those in systolic pressure, should indirect measurement of diastolic pressure become technically feasible, it might be preferable for assessing drug effects on blood pressure.     

中国原花蝽属新种及新纪录（半翅目：花蝽科）

本文记载中国花蝽科原花蝽属Anthocoris Fallen新种6个,计为:黑角原花蝽A.atricarnis sp.n.(模式产地:云南),哀牢原花蝽A.ailaoanus sp.n.(模式产地:云南),杨氏原花蝽A.yangi sp.n.(模式产地:云南),刺突原花蝽A.armatus sp.n.(模式产地:云南),萧氏原花蝽A.hsiaoi sp.n.(模式产地:四川、陕西),秀原花蝽A.concinnus sp.n.(模式产地:西藏)。文章并记录此属的3个中国新记录种;并为已被占用的A.elongatus Zheng 1982命以新名:A.longiusculus nom.nov.     

Physical maps of 4p16.3, the area expected to contain the Huntington disease mutation

The gene for Huntington disease, a neurodegenerative disorder with autosomal dominant inheritance, has been localized to the terminal portion of the short arm of human chromosome 4 (4p16.3) by linkage analysis. Since eventual isolation of the gene requires the application of high-resolution genetic analysis coupled with long-range DNA mapping and cloning techniques, we have constructed a physical map of the chromosomal region 4p16.3 using more than 20 independently derived probes. We have grouped these markers into three clusters which have been ordered and oriented by genetic and somatic cell genetic mapping information. The mapped region extends from D4S10 (G8) toward the telomere and covers minimally 5 Mb.     

新生牛肝脏生长因子的纯化及其理化特性与生物活性

新生牛肝细胞生长因子是一种热稳定、蛋白酶及酸化(pH<1.5)敏感的蛋白质或多肽。研究结果表明,它可促进肝来源的细胞系的DNA合成,但不能刺激非肝来源细胞系的DNA合成。它还可提高某些化合物(CCl_4,D-Gal)引起的急性肝衰竭小鼠的存活率。